The present invention relates to a fluoroscopic radiographing carrier apparatus or stand, which is especially used for oblique fluoroscopy, oblique radiography, and linear tomography.
When fluoroscopic radiography of a subject or patient to be examined is carried out by X-rays, the subject is put on a top plate of an X-ray fluoroscopic radiographing carrier apparatus or stand, and an X-ray tube device and an X-ray image detector provided on the opposite side of the top plate relative to the X-ray tube device, is usually used. In the X-ray fluoroscopic radiographing carrier apparatus, X-rays passing through a portion of the subject are recorded on an X-ray image detector (such as an X-ray radiographing film device, an image intensifier and a semiconductor flat panel image pickup device), or displayed on a TV monitor by converting data to electric signals and forming pictures, or memorized.
In order to diagnose or determine a location and size of an interested portion (affected part) in the subject, oblique fluoroscopy or oblique radiography, in which a direction of incidence of X-rays relative to the subject is set obliquely, is carried out. A plurality of tomograms with varying a height of a cutting plane of the subject is also taken.
An image obtained by simple radiography is displayed in a single film in a condition that all the tissues and organs of the portions taken by radiographing in the direction of the X-rays are overlapped. In tomography, an X-ray image on a plane which is intended to see is only showed clearly, and X-ray images of the portions front and behind the plane is out of focus. Accordingly, the X-ray image close to the cutting plane of the subject is only obtained.
In the tomography, a fault image is obtained by moving two among the X-ray tube device, the subject and the X-ray image detector, while synchronizing with each other. Usually, the subject is fixed, and the X-ray tube device and the X-ray image detector, such as a film, are moved.
An X-ray fluoroscopic radiographing carrier apparatus or stand which is used for oblique fluoroscopy and radiography is shown in FIG. 4. The X-ray fluoroscopic radiographing carrier 1 apparatus has an X-ray tube device 1, a stand 7 which supports the X-ray tube device 1, and an X-ray image detector 3 which detects X-rays passing through a subject or patient 8. The X-ray tube device 1 rotates around a fulcrum 10, and an oblique incident angle to the subject 8 may be changeable. Accordingly, the oblique fluoroscopy and radiography may be carried out by using the X-ray tube device 1 and the X-ray image detector 3 disposed under a top plate 4.
In the X-ray fluoroscopic radiographing carrier apparatus, since the X-ray image detector 3 is not moved sufficiently, tomography can not be carried out. The X-ray tube device 1 can be, however, set obliquely by inclining the stand 7, and the stand 7 with the X-ray tube device 1 and the X-ray image detector 3 may be moved parallel to the top plate 4. Furthermore, the top plate 4 on which the subject 8 is placed, may be moved along the longitudinal direction of the top plate.
A conventional X-ray fluoroscopic radiographing carrier apparatus or stand is composed as described above, but when the subject 8 is seen through the fluoroscope from a front, a point A is projected at a center of the X-ray image detector 3. However, when the X-ray tube 1 is located at an oblique position, a point B in the subject 8 is projected at the center of the X-ray image detector 3 and the point A in the subject 8 is projected at an edge of the X-ray image detector 3. Since an objective radiographing point is shifted for a distance corresponding to the oblique incident angle by changing the angle, the fluoroscopy and the radiography for the objective portion can not be achieved. Accordingly, it is necessary to adjust a position of the portion to be photographed in the subject by moving the top plate 4 or the stand 7 with the X-ray tube device 1 and the X-ray image detector 3 again, and it causes the problem of lowering an efficiency of diagnosis.
The present invention has been made in view of such circumstances as described above, and an object of the invention is to provide an X-ray fluoroscopic radiographing carrier apparatus or stand, wherein even if oblique fluoroscopy and oblique radiograph in which X-ray is obliquely irradiated to a subject are carried out, a projected image on an X-ray image detector is not shifted.
Further objects and advantages of the invention will be apparent from the following description of the invention.
In order to achieve the purpose as described above, an X-ray fluoroscopic radiographing carrier apparatus of the invention includes an X-ray tube device which rotates and inclines along a body axis of a subject, a stand which supports the X-ray tube device, and an X-ray image detector disposed on the side opposite to a top plate relative to the X-ray tube device. Each of the X-ray tube device, the stand and the X-ray image detector is independently moved by independent driving control means, so that oblique fluoroscopy, oblique radiography and linear tomography may be carried out.
The X-ray fluoroscopic radiographing carrier apparatus of the invention has means for moving the X-ray tube device and the X-ray image detector parallel to the top plate in order to correct a shift of a position of the projected portion in the subject, which occurs when the X-ray tube device is rotated and inclined and an oblique angle is changed.
The X-ray fluoroscopic radiographing carrier apparatus of the invention is formed as described above. Since each of the X-ray tube device, the stand and the X-ray image detector is independently moved by independent drive portions and control portions, the X-ray can always be irradiated to an interested portion in the subject, which is intended to project, in spite of changing of the oblique angle. Furthermore, since the X-ray image detector can be moved for a distance corresponding to the oblique angle, the interested portion in the subject is always projected to a center of the X-ray image detector.
While the shift of the position of the projected portion in the subject, which occurs when the X-ray tube device is rotated and inclined and the oblique angle is changed, is corrected by moving the X-ray image detector, the X-ray tube device 3 attached to the stand and the X-ray image detector 9 can be moved parallel to the top plate interposed therebetween and in the opposite directions. Accordingly, a tomography by linear moving system can be carried out.